Plaster base



R. H. CUTTING PLASTER BASE April 1, 1952 Filed Nov. 30, 1944 INVENTOR.

BY J Ma i/Lg Ilillllllfi FIGL'T ATTORNEY.

Patented Apr. 1, 1952 UNITED STATES PATENT OFFICE PLASTER BASE Richard H. Cutting, Cleveland Heights, Ohio Application November 30, 1944, Serial No. 565,891

12 Claims. 1

The present invention relates to building construction, more particularly to a plaster base and ground, and especially to a cornerbead, an accessory used by plasterers in building up external corners. The present application contains subject matter derived from and is a continuation in part of my copending application Serial No. 519,569, filed January 24, 1944, and my application Serial No. 487,859, filed May 21, 1943, both now abandoned.

External corners occur wherever offsets are formed in a room or the like and, in the case of plastered walls, the use of a cornerbead is practically indispensable to the plasterer during formation of these corners. The corner-bead serves several purposes, such as a gauge for obtaining the desired thickness of plaster, as a guide for maintaining straight, perpendicular and horizontal corner lines, and as a support for the projection of wet plaster at the corner until it has set sufficiently to become self-supporting, etc.

Heretofore, metal has been used almost exclusively for making cornerbeads, and while metal cornerbeads serve the plasterers several purposes, such as a gauge, guide, and support for the wet plaster, the combination of metal and plaster in the plaster projection at the corner does constitute somewhat of a hazard. While wet plaster sets promptly, the drying-out or curing process takes a much longer period of time and for good bonding results should be accomplished at a fairly even rate so as to permit the solids held in solution to crystallize and thus bond the whole into a homogeneous mass. During the curing period, moisture is gradually eliminated from the plaster by the processes of absorption and evaporation. However, when a metal or nonabsorbent cornerbead is employed, the elimination of moisture by absorption from the plaster of the plaster projection at the corner is practically nil. This results in an excess accumulation of moisture in the plaster projection at the corner, which seriously affects the proper crystallization and bonding of the materials at this critical location and unless the crystallization has,

taken place properly, the bond between the lime and sand of the plaster is only minor. Frequently the embedded metal cornerbead is merely enclosed by a shell of surface hardened plaster and in the event of an accidental blow, the effect is to shatter the surface for a considerable distance above and below the actual point of impact.

The principal object of the present invention is to provide a novel, improved and inexpensive,

conveniently handled, non-corrosive cornerbead which will not only serve the plasterers several purposes, such as a gauge, guide, and support for the wet plaster in the plaster projection at the corner, but which when left embedded in the wet plaster will retain its rigid properties, aid in the elimination of moisture by absorption, and in the final curing process form an excellent and enduring bond with the plaster.

Another object of the invention is to provide a novel and improved method of making a cornerbead of the character referred to comprising an outer or contact member composed essentially of a heat hardened absorbent material and an inner member of less width than the outer mem-- ber integral with the outer member adjacent to their marginal edges, which method comprises impregnating porous paper or paper-like material with a thermal resin, preferably a water soluble phenol formaldehyde resin; drying the impregnated material; fabricating the same, as by scoring, punching, creasing, bending, and affixing the inner member thereto, etc.; and subsequently heat treating the whole, without materially affecting the original porous character of the outer or contact member, to set'the resin and transform the outer or contact member into a hardened highly absorbent material in the nature of a mild plastic, which material will not swell or break down under contact with moisture.

The invention, mental principles, resides not only in certain details of construction and combinations and arrangements of parts, but also in the selection and treatment of materials, each for its particular function in relation to the whole, and further objects and advantages will be apparent to those skilled in the art to which it relates from the following description of the preferred embodiment, described with reference to the accompanying drawings forming a part of this specification, in which similar reference characters designate similar parts, and in which Fig. 1 is a perspective view, with parts in section and broken away, of an external corner of a plastered room, which corner embodies the cornerbeadof the present invention; i

Fig. 2 is a side view, with portions broken away of a piece or strip of cornerbead similar to that shown in Fig. 1 before it is applied to the wall;

Fig. 3 is a sectional view on the line 3-3 of the conerbead shown in Fig. 2; I

Fig. 4 is a view similar to Fig. 3, but showin adhering to several funda- 3 the manner in which the cornerbead unfolds as it is applied to the wall;

Fig. is a View illustrating the form in which the conerbead shown in the preceding figure is manufactured; and

Fig. 6 is a view similar to Fig. 5, but showing a cornerbead of slightly modified construction.

The cornerbead of the preesnt invention is made preferably essentially of paper and reflects throughout an understanding not only of the plasterers art but of the paper manufacturers art as well. combination of principles, a new and novel cornerbead and method of making the same have been provided, which cornerbead embraces the necessary rigid properties of metal and the absorbent properties of paper.

The improved cornerbead preferably comprises an outer or contact member of specially treated paper, and a narrower inner or reinforcing member of ordinary paper but of good strength and bondingproperties, the two being combined adjacent to their marginal edges to form the cornerhead. The paper used for the outer or contact member ishighly porous in characterand is pref erably treated by saturation by immersion in a water soluble phenol formaldehyde resin solution and air dried without pressure so as to preserve its original porous character. In this state the treated and ordinary papers are cut to their res'pective sizes and designs and combined to form the cornerbead. The completed cornerbead is thenheat treated without pressure at a temperature sufflcientlyhigh to set the resin and convert the phenol formaldehyde rosin treated paper into a mild plastic, which thereafter is resistant to any softening action of moisture. Further, as theheat treatment is accomplished without pressure, the original porous character of the paper is preserved and, consequently, it absorbs moisture very readily and dries at an even rate with the plaster, permitting the formation of an excellent bond, whereas the ordinary untreated paper used for the inner or reinforcing member is not affected by the heat treatment, retains its original strength and bonding properties, and serves to reinforce the somewhat fragile and brittle plasticlike outer member.

Referring to the drawings, Fig. 1 shows a verticalext'ernal corner, including a cornerbead embodying the present invention. The cornerbead is'designatedgenerally by the reference character A. The particular corner shown, which, of course, is merely illustrative, comprises a verti al wood stud lfl having commercial gypsum board or lath H nailed thereto. After the lath is in place, the cornerbead A is applied, and subsequently the plaster 12.

The cornerbead A shown, comprises outer and inner members [3 and M, respectively, glued or otherwisesuitably fixed together adjacent to their marginal edges. Theouter or contact member 3 3 is-wider than the, inner or reinforcing member M, with the result that the center crease, or corner forming edge lb of the. outer member l3stands away or is spaced from the inner or reinforcing member [4. The. outer or contact member 5 3 shown is made of number two (No. 2) gasket stockwhich is highly porous in character, of fair weight. and about thirty points or thousands of an inch inthickness. Alternatively, any suitable porouspaper may be employed and the particular paper referred to is merely illustrative of a satisfactory paper. One of the advantages of the particular paper mentioned, or of a paper of Consequently, through the use of a,

similar character, is the fact that it can be passed, without extraneous support, through the impregnating solution as a continuous process.

The paper selected for the outer or contact member I3 is impregnated or treated, preferably by saturation by immersion, with a water soluble phenol formaldehyde resin solution containing any suitable percentage of solids depending upon the results desired. A water soluble phenol formaldehyde solution comprising about eighteen percent (18%) to twenty-five percent (25%) solids has been found entirely satisfactory, both from the viewpoint of workability during immersion, etc., and finished product. The particular paper mentioned above can be satisfactorily saturated by immersion by passing it in a continuous manner through the aforesaid phenol formaldehyde solution containing 18% to 25% solids at room temperature and at approximately 10 to 15 per minute. After saturation by immersion. or otherwise, as the case may be, the treated paper is preferably air dried without pressure. Alternatively, the paper may be dried in any other suitable manner which will preserve the original porous character of the paper and avoid setting or hardening of the resin. The treated paper'can be dried in this manner to approximately ten percent (10%) of bone dry.

The inner member I4 may be of the same material as the outer member l3 and treated in the same manner but, preferably is formed of a lighter untreated material, such as ordinary paper stock of low absorbent properties and approximately twelve point thickness. After the paper-of. which theoutside member l3-is to be-made has been impregnated orsaturated and dried and before it is heat treated to set the resin, it is creased or scored, preferably in a conventional type of paper working machine, along the lines l5, l6 and I1 and while bent to the shape shown in Fig. 5, the, inside member I4 is fixed thereto adjacent to their marginal edges as by glue, cement or other suitable securing means. As shown, the members 13 and M are glued together between the score marks l6 and I1 and their marginal edges. The material of the member I3 between the score marks 16 and I! is considerably greater tha'n the material of the member l4 between the same score marks, with the result that the material of the member l3 between the score marks I 6 and l! forms with the material of the member l4 between the same score marks an isosceles triangle,.the apex of which is the score mark or line l5. The desired height of the; triangle referred to will be governed by the thickness of plaster desired adjacent to the corner, and the angle of the. corner to which the cornerbead is to be applied. The cornerbead is subsequently folded to the form shown in Figs. 2 and 3, and heat treated to set the resin.

The heat treatment, as'previously stated, comprises subjecting the material without pressure, such as might be effected by dies and the like, to enough heat for a sufiicient length of time to set the resin and fix the cellular structure of the paper. With the phenol formaldehyde resin mentioned above, the cornerbead is preferably heated at approximately 300 F. until all of the moisture is driven out. This treatment is enough to set the resin without otherwise affecting the paper and converts the outer member l3 into a fairly still? but somewhat bendable mild plastic or plastic-like material.

The cornerbead is preferably shipped and handled flat, that is in the form shown in Figs.

2 and 3. It is applied to the corner by being pressed or forced on or over'the corner formed by the lath, as shown in Fig. 4. As the cornerbead is pressed onto the corner, it is opened or unfolded by the corner the required amount and when in final position is nailed or otherwise firmly fixed in place. As can be readily seen from Fig. 4, the inner member I4 centers the outer member l3 on the corner and positions or holds the edge or corner IS a predetermined distance away from the former. This distance, as previously inferred, depends upon the thickness of plaster desired since the edge or corner [5 is to be used as a ground or gauge by the plasterer.

The cornerbead shown contains numerous holes 20 and 2| into which portions of the plaster [2 project to more securely fix the plaster to the cornerbead. The holes 20 which are located between the score marks or creases l6 and I! and the free edges of the cornerbeadextend through both members l3 and and the holes 2| which are located between the creases or scores l5 and I6, and I5 and I! are in the outer member l3 only. The holes referred to may be of any suitable shape. It is also to be understood that the use of holes, such as the holes 20 and 2|, is entirely optional since the plaster will bond to the material of the members l3 and M in the absence of the holes in a manner suitable to that in which plaster bonds to gypsum lath. Where holes are employed, they are punched in the member or members prior to the heat treatment because subsequent to the heat treatment the material is somewhat brittle and can be satisfactorily punched only with difficulty, if at all. Where the holes 2! are employed, the plaster which is squeezed therethrough into the space underneath the central portion of the outer member 13 when set and dry, aside from keying the plaster to the cornerbead, stiflfens or reinforces the cornerbead and in turn thecorner, thus making the construction stronger.

Referring again to the preferred construction of outside corner shown, the material of which the cornerbead is made will crush and otherwise absorb the shock when struck a blow, as by a piece of furniture or the like, at the point of impact and will not transmit it along the cornerbead. If the plaster is cracked or otherwise damaged by the blow, the damage will be confined to a relatively small area. The damaged corner may be readily repaired with plaster as the repair plaster will readily adhere to the material of which the cornerbead is made.

Referring specifically to Fig. 3, it will be seen that while the inner and outer members [4 and I3 of the strip of cornerbead shown therein are of the same length, they are slightly offset lengthwise so that one projects approximately one-half of an inch or so beyond the other. This construction, while only optional, facilitates the aligning of the adjoining ends of adjacent strips by allowing one to slightly overlap the other.

If desired, the treated paper 22, see Fig. 6, of the outside or contact member 23 of the cornerbead may be reinforced by being backed with untreated ordinary paper 24 affixed thereto subsequent to being saturated or impregnated with the resin and dried. This'pa per is preferably of good bonding properties and of approximately ten point thickness. Alternatively, an untreated paper similar to the paper 24 may be applied to either or both sides of the treated paper 22.

In addition to forming the outside or plaster contact member of a cornerbead of the character referred to, the plastic or plastic-like ma? terial of the present invention may be used as a plaster ground generally. Other uses of the material might be to cover the crack between adjoining sections of gypsum lath.

Reference to Fig. 1 will clearly show the outer member l3 of the cornerbead or, more particularly, the central portion thereof, is embedded in the plaster of the plaster projection at the corner. The moisture in this plaster, together with that in the plaster adjacent thereto, will be eliminated by absorption as well as by evaporation because of the porous and absorption characteristics of the cornerbead, with the result that the plaster dries out or cures evenly and the whole is securely bonded into a homogeneous mass;

From the foregoing, it will be apparent that the objects heretofore enumerated'and others have been accomplished and that a new and improved cornerbead and method of making the same have been provided.

While the preferred embodiment of the invention has been described in considerable detail, I do not wish to be limited to the particular construction or constructions shown and described or to the specific materials specified as these may be varied within the scope of this invention. For

example, one or more of the various pieces of paper stock employed in the preferred embodiment shown could be replaced by suitable fabric. This is especially true of the inner member I 4 and the reinforcer paper 24, and it is my intention to hereby cover all adaptations, variations and modifications, etc., thereof that come within the practice and knowledge of those skilled in the art to which the invention relates, and within the spirit or scope of the appended claims.

Having thus described my invention what I claim is:

i 1. In a cornerbead of the character described, the combination of an outer member comprising a hard rigid porous absorbent plastic-like material sheet which will not swell or break down under contact with water moisture composed essentially of porous paper of fair strength and high absorbent properties impregnated with and bonded together by a thermo-setting resin and an inner member of ordinary paper and of less width than the outer member, said members being fixed together adjacent to their marginal edges only.

2. In a cornerbead of the character described, the combination of an outer member comprising a hard rigid porous absorbent plastic-like material sheet which will not swell or break down under contact with water moisture composed essentially of paper of fair strength and high absorbent properties impregnated with and bonded together by a thermo-setting resin and an inner member of untreated ordinary paper of less width than the outer member, said members being fixed together adjacent to their marginal edges only prior to the setting of the resin of the outer'member.

' 3. In a cornerbead of the character described, the combination of an outer member comprising a hard rigid porous absorbent plastic-like member which will not swell or break down under contact with water moisture backed and reinforced by paper of good bonding properties fixed thereto, and an inner paper member of less width than the outer member, said members being integral adjacent to their marginal edges only and said plastic-like member being composed essentially of porous paper of fair strength and high absorbent properties impregnated with and bonded together by a thermosetting resin cured subsequent to aiiixing the backing paper and inner member thereto.

4. In a cornerbead of the character described, an outer member comprising a hardened absorbent plastic which will not swell or break down under contact with moisture composed essentially of paper stock of fair weight and high absorbent properties impregnated with a thermo-setting resin and subsequently heat treated to set the resin, and an inner member formed of paper stock of high strength and low absorbent properties fixed to the outer member adjacent to their marginal edges only, said inner member being of less width than theouter member whereby the said outer member is caused to stand out from the inner member when the cornerbead is applied to a corner.

5. In a cornerbead of the character described, an outer member comprising a hardened absorbent plastic which will not swell or break down under contact with moisture composed essentially of paper stock of fair weight and high absorbent properties impregnated with a thermo-setting resin and subsequently heat treated to set the resin, and an inner member formed of paper stock of high strength and low absorbent properties fixed to the outer member adjacent to their m'ar'gina ledges, said outer member having a plurality of ape'rtureas extending therethrough and said inner member being of less width than the outer member whereby the said outer member is caused to stand out from the inner member wh'enthe" cornerbead is'applied to a corner.

6. In a cornerbead of the character described, an outer member comprising a hardened absorbent plastic which will not swell or break down under contact with moisture composed essential- 1y of paper stock of fair weight and high absorbent properties impregnated with a phenol formaldehyde resin and subsequently heat treated to set the resin, and an inner member formed of paper stock of high strength and low absorbent properties fixed to the outer member adjacent to their marginal edges said inner member being of less width than the outer member whereby the said outer member is caused to stand out from the inner member when the cornerbead is applied to a corner.

7. In a cornerbead of the character described, an outer member comprising a hardened absorbent'pla'stic' which will not swell or break down underconta'ct with moisture composed essential- 1y of paper stock of fair weight and high absorbent properties impregnated with a water soluble phenol formaldehyde resin and subsequently heat' treated to set the resin, and an inner member formed of paper stock of high strength and low' absorbent properties fixed to the outer'rnembe! formed of a er stock of high strength and low'absorbeiit' properties fixed to the outer member adjacent to their marginal edges, said outer member having a plurality of apertures extending therethrough and said inner member being or less width than the outer member whereby the said outer member is caused to standout from the inner member when the cornerbead is applied to a corner.

8.- The method of making a cornerbead of the character described including an outer sheet like member comprising a hard rigid porous absorbent plastic which will not swell or break down under contact with water moisture and an inper sheet like member of less width than the outer member, which method comprises providing as an outer member a porous paper of fair weight and high absorbent properties, impregnating said paper with a phenol formaldehyde resin, drying the impregnated paper, providing an inner sheet like member of less width than the outer member, securing the two members together adjacent to their marginal edges only, and subsequently heat treating the whole without pressure to set the resin without materially affecting the original porous character of the impregnated paper.

9. The method of making a cornerbead of the character described comprising an outer sheet like member including a hard rigid porous absorbent plastic which will not swell or break down under contact with waternmoisture and an inner sheet like member of less width than the outer member secured to one side thereof adjacent to the marginal edges, which method comprises providing as an outer member a porous paper of fair weight and high absorbent properties, impregnating by saturation by immersion said paper with a water-soluble phenol formaldehyde resin, drying the impregnated paper, scoring and punching said treated paper, affixing an inner sheet like member of less width than the outer member formed of paper of high strength and low absorbent properties to one side of said outer member by securing the two members together adjacent to their marginal edges only, and subsequently heat treating the whole without pressure to set the resin without materially affecting the original porous character of the impregnated paper.

10. The method of making a cornerbead of the character described comprising an outer sheet like member including a hard rigid porous absorbent plastic which will not swell or break down under contact with water moisture and an inner sheet like member of less width than the outer member secured to one side thereof adjacent to the edges of the cornerbead, which method comprises providing as an outer member a porous paper of fair strength and high absorbent properties, impregnating said paper with a phenol formaldehyde resin, drying the impregnated paper, affixing an unimpregnated paper of good bonding properties to one side of the impregnated paper, affixing an inner sheet like member of less width than the outer member and formed of paper of high strength and low absorbent properties to one side of said outer member by securing the two members together adjacent to their marginal edges only, and subsequently heat treating the whole without pressure to set the resin without materially affecting the original porous character of the impregnated paper.

11. The method of making a cornerbead of the character described comprising an outer sheet like member including a hard rigid porous absorbent plastic which will not swell or break down under contact with water moisture and an inner sheet like member of less width than the outer member affixed thereto, which method comprises providing as an outer member a porous paper of fair weight and high absorbent properties, impregnating said paper with a phenol formaldehyde resin, drying the impregnated paper, afiixing an unimpregnated paper of good bonding properties to one side of the impregnated paper, scoring the combined material and punching a plurality of holes therein, aflixing an inner sheet like member of less width than the outer member and formed of paper of high strength and low absorbent properties to one side of said outer member by securing the two members together adjacent to their marginal edges only, and subsequently heat treating the whole without pressure to set the resin without materially affecting the original porous character of the impregnated paper.

12. A cornerbead of the character described comprising an outer sheet like member composed essentially of a hard rigid porous absorbent material which will not swell or break down under contact with water moisture and an inner sheet like member of less width that the outer member integral with said outer member adjacent to the marginal edges only.

RICHARD H. CUTTING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Baekeland Nov. 16, 1915 10 Number Name Date 1,277,904 Gesell Sept. 3, 1918 1,449,745 Clapp Mar. 27, 1923 2,021,172 Bucy Nov. 19, 1935 2,022,004 Larson Nov. 26, 1935 2,054,044 Pinten Sept. 15, 1936 2,077,017 Schacht Apr. 13, 1937 2,234,701 Lyman Mar. 11, 1941 2,291,079 Hofferbert July 28, 1942; 2,314,523 Speer Mar. 23, 1943 2,325,302 Britt July 27, 1943 2,336,086 Goldman Dec. 7, 1943 2,347,566 Komenda Apr. 25, 1944 2,410,078 Kellgren Oct. 29, 1946 2,422,423 Kvalnes June 17, 1947 2,437,082 Davis Mar. 2, 1948 2,463,856 Dickerman Mar. 8, 1949 FOREIGN PATENTS Number Country Date 501,514 Great Britain Feb. 20, 1939 523,185 Great Britain July 8, 1940 539,331 Great Britain Sept. 5, 1941 557,182 Great Britain Nov. 9, 1943 OTHER REFERENCES Ser. No. 92,371, Vogele (A. 

